US 8,583,302 B2 · Assignee: Honda Motor Co., Ltd. · Inventors: Akimoto; Kazushi et al.
Sheet 1 of 18 from the published document. All sheets in the USPTO PDF
An electric vehicle includes a base; a front wheel that can be driven omnidirectionally; a rear wheel that is mounted on the base so that a symmetry axis is parallel with a symmetry axis of the front wheel; a seat member that is mounted so that a straight line connecting a wheel center of the front wheel and a wheel center of the rear wheel specifies a fore-and-aft direction; an controller that detects an acceleration and deceleration command and a turning command; an inclination sensor that detects inclination of the base; and a control unit that controls acceleration and deceleration of the base based on the acceleration and deceleration command detected by the controller, that controls turning of the base based on the turning command detected by the controller, and that controls translational motion of the base based on inclination of the base detected by the inclination sensor.
A small size electric vehicle including a structure that is adapted for low-speed running has been conventionally used to facilitate use by the elderly, disabled persons or the like. An example of this type of electric vehicle is a four-wheeled electric vehicle 200 shown in FIG. 22 (for example refer to Japanese Unexamined Patent Application, first publication No. 2006-102387). A driving unit of the electric vehicle 200 drives and rotates rear wheels 203. The vehicle body 201 is driven (running) forward or backward by the rotation of the rear wheels 203. The vehicle body 201 is turned by varying the direction of the front wheel 202 by operating a steering unit 205. The electric vehicle 200 can be driven forward or backward, and also can be turned to the right or left while being driven forward or backward. However the electric vehicle 200 cannot be driven directly to the side. It is an e
1 of 18 drawing sheets so far from the published document, cropped to the drawing. Every sheet is in the USPTO PDF.
What the patent claimed, word for word. All of it is now free to use.
The present application claims priority from Japanese Patent Application No. 2009-219761 filed on Sep. 24, 2009, the contents of which are incorporated herein by reference.
The present invention relates to an electric vehicle.
A small size electric vehicle including a structure that is adapted for low-speed running has been conventionally used to facilitate use by the elderly, disabled persons or the like.
An example of this type of electric vehicle is a four-wheeled electric vehicle 200 shown in FIG. 22 (for example refer to Japanese Unexamined Patent Application, first publication No. 2006-102387). A driving unit of the electric vehicle 200 drives and rotates rear wheels 203. The vehicle body 201 is driven (running) forward or backward by the rotation of the rear wheels 203. The vehicle body 201 is turned by varying the direction of the front wheel 202 by operating a steering unit 205.
The electric vehicle 200 can be driven forward or backward, and also can be turned to the right or left while being driven forward or backward. However the electric vehicle 200 cannot be driven directly to the side.
It is an exemplary object of an exemplary embodiment of the present invention to solve the above problems, and to provide an electric vehicle which enables instructions for being driven directly to the side while using an interface of a conventional operation system.
An electric vehicle according to an aspect comprises a base; a movement operator that has at least one omnidirectional drive wheel which can be driven omnidirectionally; a seat member that is mounted on the base; an acceleration and deceleration command unit that detects an acceleration and deceleration command; a turning command unit that detects a turning command; an inclination detection unit that detects an inclination of the base; and a control unit that controls acceleration and deceleration of the base based on the acceleration and deceleration command detected by the acceleration and deceleration command unit, that controls turning of the base based on the turning command detected by the turning command unit, and that controls translational motion of the base based on the inclination of the base detected by the inclination detection unit.
In this manner, the acceleration and deceleration command unit can detect an acceleration and deceleration command, the turning command unit can detect a turning command and the inclination detection unit can detect an inclination of the base. The control unit can control acceleration and deceleration of the base based on an acceleration and deceleration command detected by the acceleration and deceleration command detection unit, can control turning of the base based on a turning command detected by the turning command unit, and can control translational motion of the base based on an inclination of the base detected by the inclination detection unit.
In the electric vehicle according to other aspects, the control unit controls the turning of the base so that incline the base during the turning. In this manner, the electric vehicle can move during turning with the base inclined.
The electric vehicle according to another aspect may comprise a rotation center position determination unit that determines a position of the rotation center during turning at least according to a velocity of the base or an acceleration of the base. In this manner, the electric vehicle can turn about the position of a rotation center according to a velocity or acceleration.
The electric vehicle according to another aspect comprise a base; a first omnidirectional drive wheel that is mounted on the base and can be driven omnidirectionally; a second omnidirectional drive wheel that is mounted on the base so that a symmetry axis thereof is parallel with a symmetry axis of the first omnidirectional drive wheel; a seat member that is mounted so that a straight line connecting a wheel center of the first omnidirectional drive wheel and a wheel center of the second omnidirectional drive wheel specifies a fore-and-aft direction; an acceleration and deceleration command unit that detects an acceleration and deceleration command; a turning command unit that detects a turning command; an inclination detection unit that detects inclination of the base; and a control unit that controls acceleration and deceleration of the base based on the acceleration and deceleration command detected by the acceleration and deceleration command unit, that controls turning of the base based on the turning command detected by the turning command unit, and that controls translational motion of the base based on inclination of the base detected by the inclination detection unit.
In this manner, the acceleration and deceleration command unit can detect an acceleration and deceleration command, the turning command unit can detect a turning command and the inclination detection unit can detect an inclination of the base. The control unit can control acceleration and deceleration of the base based on an acceleration and deceleration command detected by the acceleration and deceleration command detection unit, can control turning of the base based on a turning command detected by the turning command unit, and can control translational motion of the base based on an inclination of the base detected by the inclination detection unit.
In the electric vehicle according to another aspect, the straight line above may be parallel to a fore-and-aft direction of the seat member.
In this manner, the electric vehicle can move in a fore-and-aft direction of the seat member along a direction of the straight line connecting the center of the wheels.
According to the aspects as described above, the acceleration and deceleration command unit can detect an acceleration and deceleration command, the turning command unit can detect a turning command and the inclination detection unit can detect an inclination of the base. The control unit can control acceleration and deceleration of the base based on an acceleration and deceleration command detected by the acceleration and deceleration command detection unit, can control turning of the base based on a turning command detected by the turning command unit, and can control translational motion of the base based on an inclination of the base detected by the inclination detection unit. In this manner, the electric vehicle is enabled for translational motion according to an inclination of the base in addition to acceleration and deceleration according to an acceleration and deceleration command or turning according to a turning command.
According to the aspects as described above, since the base is inclined during turning, stable riding comfort is also enabled during turning.
According to the aspects as described above, natural turning is enabled by turning about the rotation center position according to the velocity or the acceleration.
According to the aspects as described above, the fore-and-aft direction of the seat member is parallel to a straight line connecting the wheel center of the first omnidirectional drive wheel and the wheel center of the second omnidirectional drive wheel. In this manner riding comfort can be improved.
FIG. 1 is a perspective view seen from the front side of an electric vehicle of an exemplary embodiment.
FIG. 2 is a perspective view seen from the rear side of an electric vehicle of the exemplary embodiment.
FIG. 3 is a back view seen from the rear side of an electric vehicle of the exemplary embodiment.
FIG. 4 is an enlarged sectional view of a rear wheel of the exemplary embodiment.
FIG. 5 is a perspective view of a rear wheel of the exemplary embodiment.
FIG. 6 is a perspective view of a main wheel of the exemplary embodiment.
FIG. 7 is a view illustrating a positional relationship between the main wheel and a free roller in the exemplary embodiment.
FIG. 8 is an upper view showing the driving directions of the front wheel and the rear wheel when the electric vehicle of the exemplary embodiment performs translational motion.
FIG. 9 is an upper view showing the driving directions of the front wheel and the rear wheel when the electric vehicle of an exemplary embodiment performs turning.
FIG. 10 is a flowchart showing a main routine process of a control unit according to the present aspect.
FIG. 11 is a schematic view showing an inverted-pendulum model expressing the dynamic behavior of the electric vehicle of the exemplary embodiment.
FIG. 12 is a functional block diagram of a control unit of the exemplary embodiment.
FIG. 13 is a functional block diagram of a gain adjustor of the exemplary embodiment.
FIG. 14 is a functional block diagram of a limiting processor of the exemplary embodiment.
FIG. 15 is a schematic view showing a rotation center position of an electric vehicle of the exemplary embodiment.
FIG. 16 shows the relationship between inclination of a controller and a value of R_front and a value of R_rear in the exemplary embodiment.
FIG. 17 is a functional block diagram of a gravity center velocity restrictor of the exemplary embodiment.
FIG. 18 is a functional block diagram of a posture control calculation restrictor of the exemplary embodiment.
FIG. 19 is a perspective view seen from the front side of a three-wheeled electric vehicle.
FIG. 20 is a perspective view seen from the front side of a four-wheeled electric vehicle.
FIG. 21 is a perspective view seen from the rear side of an electric vehicle in which a seat member is rotated through 90.degree. about the Z axis.
FIG. 22 is a side view showing a conventional electric vehicle.
Exemplary embodiments of the present invention will be described hereafter with reference to the attached figures.
FIG. 1 is a perspective view seen from the front side of an electric vehicle. FIG. 2 is a perspective view seen from the rear side of the electric vehicle.
As shown in FIG. 1 and FIG. 2, the electric vehicle 1 of the exemplary embodiment comprises a vehicle body 2 (base), a front wheel 3 (first omnidirectional drive wheel) and a rear wheel 4 (second omnidirectional drive wheel), and a seat member 150 enabling seating by a driver (user) D in a forward direction of the electric vehicle 1. Both the front wheel 3 and the rear wheel 4 are an omnidirectional vehicle, and are mounted in a front and a rear side of the vehicle body 2. The seat member 150 is disposed above the rear wheel 4.
The vehicle body 2 comprises a step floor 159, a front wheel fender 157 and a rear wheel fender 158, and connecting portion 160. The step floor 159 forms a bridge between the front wheel 2 and the rear wheel 4. The front wheel fender 157 and the rear wheel fender 158 configure the front wheel 3 and the rear wheel 4. The connecting portion 160 connects the rear wheel fender 158 and the seat member 150.
The step floor 159 is a flat plate shape member that extends parallel to the road surface T (FIG. 3) and maintains an interval with the road surface T. The foot of the driver D, luggage, or the like can be loaded onto the upper surface of the step floor 159. The front wheel fender 157 of the front wheel 3 is connected to a front end portion of the step floor 159. The rear wheel fender 158 of the rear wheel 4 is connected to a rear end portion of the step floor 159.
The connecting portion 160 is a cylindrical member that is extended upwards. The lower end of the connecting portion 160 is connected to an upper portion of the rear wheel fender 158. The seat member 150 is connected to the upper end of the connecting portion 160.
The seat member 150 comprises an L-shaped seat portion 12 when viewed sideward for enabling a driver D to ride thereon, and a base portion 180 connecting the seat portion 12 and the connecting portion 160 described above. The seat portion 12 comprises a seat surface portion 13 and a seat back 15. The seat surface portion 13 extends in a fore-and-aft direction (horizontal direction) to thereby support the buttocks and femoral region of the driver D. The seat back 15 extends upwardly from the rear end of the seat surface portion 13 and supports the back of the driver D. In the following description, the seat portion is used for the same meaning as the seat member some times, unless specified explanations are given.
A pair of arm rests 16 extending forward from an intermediate portion of the seat back 15 in a height direction is provided on both end portions on the right and left of the seat back 15. These arm rests 16 are supported to enable rotation about a pitch axis (axis orthogonal to the fore-and-aft direction) with respect to the seat back 15. A controller 6 is provided on the distal end of the arm rest 16 to enable manual steering of the moving operation of the electric vehicle 1 by the driver D. A railing 18 extending along the lateral direction (the direction of the arrow in the figure, the right and left direction when the driver D is seated) is provided on the upper end of the seat back 15. Luggage such as a bag can be fastened onto the railing 18. A retractable luggage carrier 17 is provided on a rear side of the seat back 15. The luggage carrier 17 is supported to enable inclination about a pitch axis on the lower end of the seat back 15. More specifically, the luggage carrier 17 is disposed to enable substantially parallel extension to the seat back 15 when not in use (refer to FIG. 2). On the other hand, when in use, the carrier 17 is inclined to a position that is substantially orthogonal to the seat back 15 (refer to FIG. 1) to thereby enable loading of luggage or the like onto an upper surface thereof.
The upper end of the base portion 180 is connected to a lower face of the seat surface portion 13. The lower end of the base portion 180 is connected to an upper end of the connecting portion though a driving unit (not shown). The seat member 150 can be rotated about the yawing axis (normal line of the road surface T (refer to FIG. 4) by the driving unit (refer to M in FIG. 1).
FIG. 3 is a back view seen from the rear side of the electric vehicle. Those aspects of configuration that are the same as FIG. 1 and FIG. 2 are denoted by the same reference numerals. The overall gravity center G (center-of-gravity point) combining the driver D and the electric vehicle 1 is shown in FIG. 3.
FIG. 4 is an enlarged sectional view of the rear wheel. FIG. 5 is a perspective view of the rear wheel. FIG. 6 is a perspective view of a main wheel. FIG. 7 illustrates the positional relationship between the main wheel and a free roller. Since the front wheel and the rear wheel have the same configuration, the following description will use the rear wheel for the purposes of example. Furthermore FIG. 4 only shows a portion of the main wheel and the rear wheel fender as a sectional view.
As shown by FIG. 4 through FIG. 7, the rear wheel 4 comprises a main wheel 5 formed as a circle from a rubber-based elastic material or the like. The main wheel 5 has a substantially circular transverse sectional shape. The elastic deformation of the main wheel 5 enables rotation of the main wheel 5 about the center C1 of the circular sectional face (more specifically, the circumference line passing through the circular sectional face center C1 and concentric with the center of the main wheel 5) as shown by Y1 in FIG. 6 and FIG. 7.
The main wheel 5 is disposed on an inner side of the rear wheel fender 158 in a state in which the axis C2 thereof coincides with the lateral direction of the electric vehicle 1 (the axis C2 orthogonal to the overall diametrical direction of the main wheel 5), and is placed in contact with the road surface T on a lower end of the outer peripheral face of the main wheel 5. The rear wheel fender 158 is a dome shaped member formed as a circle when viewed from the side, and opens downwardly to thereby cover the entire rear wheel 4 with the exception of the lower end.
The main wheel 5 can performs an operation (an operation of rotating on the road surface T) of rotating about the axis C2 of the main wheel 5 as shown by Y2 in FIG. 6 as a result of driving by an actuator 7 (described in detail hereafter) and an operation of rotating about the transverse sectional center C1 of the main wheel 5. As a result, the main wheel 5 can move in all directions (can perform omnidirectional movement) on the road surface T as a result of the composite operation of these rotating operations.
The actuator 7 comprises a rotation member 27R and a free roller 29R interposed between the main wheel 5 and the right wall 21R of the rear wheel fender 158, a rotation member 27L and a free roller 29L interposed between the main wheel 5 and the left wall 21L of the rear wheel fender 158, an electric motor 31R acting as an actuator disposed above the rotation member 27R and the free roller 29R, and an electric motor 31L acting as an actuator disposed above the rotation member 27L and the free roller 29L.
The respective housings of the electric motors 31R and 31L are respectively mounted on both side walls 21R, 21L of the rear wheel fender 158. Although this has been omitted from the figures, a power source (capacitor) for the electric motors 31R, 31L is mounted in a suitable position in the vehicle body 2.
The rotation member 27R is supported to rotate on the right side wall 21R by a support shaft 33R that has a transverse axis (shaft center in lateral direction). In the same manner, the rotation member 27L is supported to rotate on the left side wall 21L by a support shaft 33L that has a transverse axis. In this case, the rotation axis of the rotation member 27R (axis of the support shaft 33R) and the rotation axis of the rotation member 27L (axis of the support shaft 33L) are coaxial.
The rotation members 27R, 27L are connected to an output axis of the respective electric motors 31R, 31L through a drive force transmission unit that includes a function as a speed reducer. The rotation members 27R, 27L are driven and rotated by a drive force (torque) transmitted respectively from the electric motors 31R, 31L. Each drive force transmission unit has a pulley and belt configuration for example. In other words, as shown in FIG. 4, the rotation member 27R is connected to the output axis (output shaft) of the electric motor 31R through the pulley 35R and the belt 37R. In the same manner, the rotation member 27L is connected to the output axis of the electric motor 31L through the pulley 35L and the belt 37L.
The drive force transmission unit described above may be configured by a sprocket and link chain, or may be configured by a plurality of gears. Furthermore, for example, the electric motors 31R, 31L may be opposed to each rotation member 27R, 27L so that the respective output axes of the electric motors 31R, 31L are coaxial to the respective rotation members 27R, 27L to thereby connect the respective output axes of the electric motors 31R, 31L to the rotation members 27R, 27L through the speed reducer (planetary gear apparatus or the like).
Each rotation member 27R, 27L is formed in the same shape as a circular truncated cone that has a reduced diameter with respect to the main wheel 5 and in which an outer peripheral surface thereof forms a tapering outer peripheral surface 39R, 39L.
A plurality of free rollers 29R are arranged in equal intervals on a circumference that is concentric with the rotation member 27R on a periphery of the tapering outer peripheral surface 39R of the rotation member 27R. These free rollers 29R are respectively mounted on the tapering outer peripheral surface 39R through a bracket 41R, and are supported to rotate on the bracket 41R.
In the same manner, a plurality of free rollers 29L (same number as the free rollers 29R) are arranged in equal intervals on a circumference that is concentric with the rotation member 27L on a periphery of the tapering outer peripheral surface 39L of the rotation member 27L. These free rollers 29L are respectively mounted on a tapering outer peripheral surface 39L through a bracket 41L, and are supported to rotate on the bracket 41L.
The main wheel 5 is sandwiched by the free roller 29R near the rotation member 27R and the free roller 29L near the rotation member 27L, and is disposed concentrically to the rotation members 27R, 27L.
As shown in FIG. 7, the axes C3 of the free rollers 29R, 29L incline with respect to the axis C2 of the main wheel 5 and are disposed in an orientation which inclines with respect to the diametrical direction of the main wheel 5 (when the main wheel 5 is viewed from the direction of its axis C2, the direction of the diameter connecting the axis C2 with each free roller 29R, 29L). In this orientation, the respective outer peripheral surfaces of each free roller 29R, 29L are respectively pressed in contact in an inclining direction onto the inner peripheral face of the main wheel 5.
More generally, when the rotation member 27R is driven to rotate about the axis C2, the right side free roller 29R is pressed into contact with an inner peripheral face of the main wheel 5 in an orientation in which, on the contact face with the main wheel 5, a frictional force component in a direction about the axis C2 (frictional force component of a tangential direction with respect to the inner periphery of the main wheel 5) and a frictional force component in a direction about the transverse sectional center C1 of the main wheel 5 act on the main wheel 5. The same comments apply to the left side free roller 29L.
The front wheel 3 is configured in the same manner as the rear wheel 4 described above. The front wheel 3 and the rear wheel 4 are disposed so that the mutual axes (rotation axis) C2 of the main wheel 5 are parallel (refer to FIG. 1 and FIG. 2). When the rotation members 27R, 27L are rotated and driven at the same velocity in the same direction by the electric motors 31R, 31L of the front wheel 3 and the rear wheel 4, the main wheel 5 rotates about the axis C2 in the same direction as the rotation members 27R, 27L. In this manner, each main wheel 5 rotates in a forward or a backward (rearward) direction on the road surface T, and drives the overall electric vehicle 1 in a forward or a backward direction. In this case, the main wheel 5 does not rotate about its transverse sectional center C1.
For example, when the rotation members 27R, 27L are rotated at the same velocity in mutually opposed directions, each main wheel 5 rotates about its transverse sectional center C1. In this manner, each main wheel 5 moves with respect to the direction of the axis C2 (in other words, the lateral direction), and the overall electric vehicle 1 is driven (moves) in a lateral direction. In this case, the main wheel 5 does not rotate about its axis C2.
When the rotation members 27R, 27L are rotated in the same direction or in opposite directions at mutually different velocities (a speed including a direction), each main wheel 5 rotates about the axis C2 and at the same time rotates about the transverse sectional center C1.
At this time, the main wheel 5 is driven in an inclining direction with respect to the fore-and-aft direction and the lateral direction due to the composite action (synthetic action) of these rotation actions, and the overall electric vehicle 1 is driven (moves) in the same direction as the main wheel 5. The moving direction of the main wheel 5 varies depending on a difference in the rotation velocity including the rotation direction of the rotation members 27R, 27L (a rotation velocity vector having polarity defined by the rotation direction).
Since the movement of each main wheel 5 is executed as described above, the moving velocity and the moving direction of the electric vehicle 1 can be controlled by controlling the respective rotation velocities (including rotation direction) of the electric motors 31R, 31L, and consequently by controlling of the rotation velocity of the rotation members 27R, 27L.
Next, the configuration for controlling the operation of the electric vehicle 1 of the exemplary embodiment will be described. In the following description, as shown in FIG. 1 and FIG. 2, an XYZ coordinate system is imaged in which the horizontal axis in a fore-and-aft direction is the X axis, the horizontal axis in the lateral direction is the Y axis, and the vertical direction is the Z axis. The fore-and-aft direction and the lateral direction are respectively called the X axis direction and the Y axis direction sometimes.
In the present aspect, the electric vehicle 1 moves in the Y axis direction using the two methods of translational motion in which the front wheel 3 and the rear wheel 4 are driven in the same Y axis direction, and of turning in which the front wheel 3 and the rear wheel 4 are driven in opposite Y axis directions.
FIG. 8 is an upper view showing the driving direction of the front wheel 3 and the rear wheel 4 when an electric vehicle 1 performs translational motion. In the example shown in the figure, the front wheel 3 and the rear wheel 4 are driven in the same direction so that the electric vehicle 1 perform translational motion to the left. FIG. 9 is an upper view showing the driving direction of the front wheel 3 and the rear wheel 4 when an electric vehicle performs turning. In the example shown in the figure, the front wheel 3 and the rear wheel 4 are driven in mutually opposite directions so that the electric vehicle 1 is turned to the left.
Firstly, the schematic operational control of the electric vehicle 1 will be described. In the electric vehicle 1 according to the present embodiment, basically when the driver D seated in the seat portion 12 inclines the controller 6, a movement operation on the main wheels 5 is controlled so that the electric vehicle 1 is moved to the side to which the controller 6 is inclined. Furthermore, when the driver D does not operate the controller 6, and applies their body weight to the right or the left, the electric vehicle 1 undergoes translational motion towards the side to which the body weight is applied. These operations form a single basic steering operation in relation to the electric vehicle 1 (operation request for the electric vehicle 1), and the movement operation of the main wheels 5 is controlled through an actuator 7 in response to this steering operation.
More specifically, the electric vehicle 1 moves in response to the angle at which the controller 6 is inclined, or the angle of inclination of the electric vehicle 1 resulting from application of the body weight of the driver D to the right or the left when the controller 6 is not inclined. To prevent overturning of the electric vehicle 1, a target posture for the vehicle body 2 is configured as the posture when the gravity center G of the electric vehicle 1 (and the entire body of the driver D) is in a position substantially directly above the central point of the rear wheel 4 (more specifically, a state in which the gravity center G seen from the fore-and-aft direction of the electric vehicle 1 is in a position substantially directly above the contact point of the rear wheel 4 (the point on the road surface T at which the distance to the gravity center is the shortest)). More specifically, the front wheel 3 and the rear wheel 4 are controlled to make the actual posture of the vehicle body 2 converge on the target posture.
In other words, the movement operation of the front wheel 3 and the rear wheel 4 is controlled so that the vertical direction of the electric vehicle 1 coincides with the direction of gravity. More specifically, when it is determined that the gravity center G has moved in a lateral direction in relation to the target posture, each main wheel 5 is rotated about the center C1 to thereby move the electric vehicle 1 in a lateral direction. Alternatively, the posture of the vehicle body 2 is caused to converge on the target posture as a result of the composite operation of these rotation operations. Therefore when it is desired to make the electric vehicle 1 performs translational motion, the gravity center of the driver D inclines to the right or to the left. In this manner, the electric vehicle 1 moves to the left or the right in order to maintain the target posture. Furthermore when it is desired to make the electric vehicle 1 move forward and backward, or move to the right or the left while moving forward or backward, the driver D inclines the controller 6 in the direction in which the driver D wants to travel. Thus the electric vehicle 1 moves forward and backward, or moves to the right or the left while moving forward or backward in response to the inclination detected by the controller 6.
To perform the above operations, in the present embodiment, a control unit (control portion) 50 configured from an electric circuit unit including a drive circuit unit of the electric motor 31R, 31L or a microcomputer, a controller 6 that detects an instruction for a moving direction of the electric vehicle 1, an inclination sensor 52 that measures the inclination angle .theta.b with respect to the direction of gravity of a predetermined position of the vehicle body 2 and its rate of change (=d.theta.b/dt), a load sensor 54 that detects whether or not a driver D is ridden on the electric vehicle 1, and a rotary encoder 56R, 56L that is an angle sensor for detecting the rotation angle and the rotation angular velocity of the output axis of the respective electric motors 31R, 31L (refer to FIG. 4) are mounted in an appropriate position in the electric vehicle 1.
The control unit 50 and the inclination sensor 52 for example are mounted and housed in an inner portion of the vehicle body 2. The load sensor 54 is mounted inside the seat portion 13. Furthermore the rotary encoders 56R, 56L are respectively integrated with the electric motors 31R, 31L. The rotary encoders 56R, 56L may be respectively mounted on the rotation member 27R, 27L.
In further detail, the inclination sensor 52 is composed of an acceleration sensor and a rate sensor such as a gyro sensor (angular velocity sensor). Detection signals from these sensors are output to a control unit 50. The control unit 50 calculates a measured value of the inclination angle .theta.b with respect to a vertical direction, and a measured value of the inclination angular velocity .theta.bdot that is its rate of change (derivative value), at the mounting position of the inclination sensor 52 by executing a predetermined measurement calculation process (this is a known calculation process) based on the output of the acceleration sensor and the rate sensor of the inclination sensor 52.
The measured inclination angle .theta.b (hereinafter, this may be referred to as the base inclination angle .theta.b) is more particularly composed of a component .theta.b_x about the Y axis (pitch direction) and a component .theta.b_y about the X axis (roll direction). In the same manner, the measured inclination angular velocity .theta.bdot (hereinafter, this may be referred to as the base inclination angular velocity .theta.bdot) is similarly composed of a component .theta.bdot_x about the Y axis (pitch direction) (=d.theta.b_x/dt) and a component .theta.bdot_y about the X axis (roll direction) (=d.theta.b_y/dt).
In the description of the present embodiment, when a variable for the motion state amount or the like that includes a component for the respective directions of the X axis and the Y axis (or a direction about each axis) such as the base inclination angle .theta.b, or a variable such as a coefficient related to the motion state amount, makes a distinction with respect to each such component by way of notation, the suffix "_x" or "_y" is added to the reference symbol for the variable.
The variables related to translational motion such as translational velocity or the like add the suffix "_x" to components for the X axis direction and add the suffix "_y" to components for the Y axis direction.
On the other hand, variables related to rotation motion such as angle or rotation velocity (angular velocity) or angular acceleration or the like add the suffix "_x" to components around the Y axis and add the suffix "_y" to components around the X axis in order to arrange the suffixes and the variables related to translational motion.
When notating the variable as a group including the component in the X axis direction (or the component around the Y axis) and the component in the Y axis direction (or the component around the X axis), the suffix "_xy" is added to the notation for the variable. For example, when expressing the base inclination angle .theta.b as a group including the component .theta.b_x around (about) the Y axis and the component .theta.b_y around the X axis, the notation "base inclination angle .theta.b_xy" is used.
The load sensor 54 is installed in the seat portion 13 to support a load resulting from the weight of the driver when the driver is seated on the seat portion 13, and outputs a detection signal corresponding to that load to the control unit 50. The control unit 50 determines whether or not a driver is ridden on the electric vehicle 1 based on the measured value of the load indicated by the output of the load sensor 54.
In substitution for the load sensor 54, for example, a switching-type sensor that is placed in the ON position when a driver is seated on the seat portion 13 can be used.
The rotary encoder 56R generates a pulse signal for each rotation through a predetermined angle of the output axis of the electric motor 31R and outputs the pulse signal to the control unit 50. The control unit 50 measures the rotation angle of the output axis of the electric motor 53R based on the pulse signal, and measures the rate of change of time (differential value) of the measured value of the rotation angle as the rotation angular velocity for the electric motor 53R. The same comments apply to the rotary encoder 56L of the electric motor 31L.
The control unit 50 determines a velocity command that is a target value of the respective rotation angular velocity of the electric motors 31R, 31L by executing a predetermined calculation process using each measured value above. The respective rotation angular velocities of the electric motors 31R, 31L are feedback controlled according to the velocity command.
The relationship between the rotation angular velocity of the output axis of the electric motor 31R and the rotation angular velocity of the rotation member 27R is proportional to the speed decrease ratio of a fixed value between the output axis and the rotation member 27R. In the description of the present embodiment, for the sake of convenience, the rotation angular velocity of the electric motor 31R means the rotation angular velocity of the rotation member 27R. In the same manner, the rotation angular velocity of the electric motor 31L means the rotation angular velocity of the rotation member 27L.
The control processing performed by the control unit 50 will be described in further detail hereafter.
The control unit 50 executes process shown by the flowchart shown in FIG. 10 at a predetermined control processing cycle (main routine processing).
Firstly in a step S1, the control unit 50 obtains the output of the inclination sensor 52 and the moving direction information indicating the moving direction which is inputted into the controller 6.
Then the processing proceeds to step S2, and the control unit 50 calculates the measured value .theta.b_xy_s for the base inclination angle .theta.b and the measured value .theta.bdot_xy_s for the base inclination angular velocity .theta.bdot based on the obtained output of the inclination sensor 52.
However in the present embodiment, since the electric vehicle 1 is a two-wheeled vehicle, the following description will be simplified by making the measured value .theta.b_x_s of the base inclination angle .theta.b in the X direction take a value of 0 (.theta.b_x_s=0), and the measured value .theta.bdot_x_s of the base inclination angular velocity .theta.bdot take a value of 0 (.theta.bdot_x_s=0).
In the following description, when the actually observed value (the measured value or the estimated value) for a variable (state amount), such as the measured value .theta.bdot_xy_s or the like, is denoted by a reference symbol, the suffix "_s" will be added to the reference symbol of the variable.
Next the control unit 50 in a step S3 obtains the output of the load sensor 54 and then executes a determination process in a step S4. In the determination process, the control unit 50 determines whether or not a driver is ridden on the electric vehicle 1 (whether or not a driver is seated on the seat portion 13) by determining whether or not the load measured value indicated by the obtained output of the load sensor 54 is greater than a predetermined value which is set in advance.
When the determination result of the step S4 is affirmative, the control unit 50 executes a process of setting a target value .theta.b_xy_obj of the base inclination angle .theta.b and a process of setting a constant parameter value (a base value for various types of gain or the like) for operational control of the electric vehicle 1. These processes are executed respectively in steps S5 and S6.
In the step S5, the control unit 50 sets a preset target value for riding mode (boarding mode) as a target value .theta.b_y_obj for the base inclination angle .theta.b in the Y axis direction.
As used herein, "riding mode" means the operational mode of the electric vehicle 1 when a driver is ridden on the electric vehicle 1. The target value .theta.b_y_obj for the riding mode is preset (set in advance) to coincide with or substantially coincide with the measured value .theta.b_y_s for the measured base inclination angle .theta.b based on the output of the inclination sensor 52 with respect to a posture of the base 9 in which the overall gravity center of the driver seated on the seat portion 13 and the electric vehicle 1 (hereinafter referred to as the overall gravity center of the electric vehicle and the driver) is positioned substantially directly above the floor surface (ground contact surface) of the vehicle wheel 5.
Then in step S6, the control unit 50 sets a preset riding mode value as a constant parameter value for operational control of the electric vehicle 1. The constant parameter includes values such as hx, hy, Ki_a_x, Ki_b_x, Ki_a_y, Ki_b_y (i=1, 2, 3) and will be described below.
When the determination result in the step S4 is negative, the control unit 50 executes a process of setting the target value .theta.b_y_obj of the base inclination angle .theta.b_y in the Y axis direction and a process of setting a constant parameter value for operational control of the electric vehicle 1. These processes are executed respectively in steps S7 and S8.
In the step S7, the control unit 50 sets the preset target value for autonomous mode as the target value .theta.b_y_obj of the inclination angle .theta.b.
As used herein "autonomous mode" means an operational mode of the electric vehicle 1 in which a driver is not ridden on the electric vehicle 1. The target value .theta.b_y_obj for autonomous mode is preset to coincide with or substantially coincide with the measured value .theta.b_y_s for the measured base inclination angle .theta.b based on the output of the inclination sensor 52 with respect to a posture of the base 9 in which the gravity center of the electric vehicle 1 alone (hereinafter referred to as the electric vehicle single gravity center) is positioned substantially directly above the floor surface of the vehicle wheel 5. The target value .theta.b_y_obj for autonomous mode is generally different from the target value .theta.b_y_obj for riding mode.
The description continues in the full USPTO document.
About 6,857 words. The USPTO PDF has it with every drawing.
Fees are due 3.5, 7.5 and 11.5 years after grant. This patent expired on November 12, 2025, so the fee marked "not paid" was the one that went unpaid.
ELECTRIC VEHICLE
Filed Sep 2010 · published Mar 2011Electric vehicle
Filed Sep 2010 · granted Nov 2013Earlier publications, parents and continuations. None of them can still be enforced, or this patent would not be listed.
Prior art cited by the examiner or applicant. Useful when you check your own idea for novelty.
Everything on this page comes from the documents linked above.
